If you need an axle replacement because one is damaged, you will be fine sticking with the 7,000 lb axles you currently have. All you would need to do is get the hub face to hub face measurement to choose the right axle length. We have 94" # 8327864 and 95" # 8327834 7k Dexter axle replacements. Unfortunately, we do not have any 8,000 lb axles available.
I suspect the reason you want to add 8k axles is based on the GVWR of your 2018 Grand Design Momentum 351. The one thing you need to... view full answer...